Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus)

Legal status in WI: Endangered Length: 2 to 3 feet

History || Description || Habitat || Range || Breeding Biology || Habits || Food Habits || Rattlesnake Bites || Status in Wisconsin || Management and Research || What can you do || Excerpt from the Animal Guide

For information on Wisconsin's snakes including an identification key and more, order your copy of Snakes of Wisconsin.

Even though you may have never seen the eastern massasauga, if it were called "swamp rattler" you would get a very vivid picture of this animal. You may imagine the massasauga to be a vicious serpent, poised and ready to strike. The term rattlesnake immediately strikes fear in the hearts of most people. This is the product of years of bad publicity for a species that is in reality very shy and secretive. The massasauga is one of the two poisonous snakes in Wisconsin, the timber rattlesnake being the other. Until 1975 there was a bounty(a fee paid to people who kill "pest" species) in Wisconsin on rattlesnakes, paying up to 5 dollars a tail. In 1975 the bounty was lifted and the massasauga was placed on the Wisconsin Endangered and Threatened Species List. Some people feared that as a result of this new protection, the massasauga would multiply out of control, but in fact their numbers appear to be steadily declining. While habitat loss continues to be a factor, the number of snakes harvested for bounty may have reduced the population to such low levels that recovery is not occurring in some areas of the state.

The adult massasauga is usually two to three feet in length, while the adult timber rattler is usually longer than three feet. The massasauga has chocolate brown backsaddles and triple rows of brownish-black side patches which merge with a marbled dark gray or black belly. Body patches appear edged in black. The tail has five to seven dark cigarband rings and is tipped by a grayish-yellow rattle. The head is flattened and broad with one white and three dark stripes radiating from it’s face. Nine enlarged plate scales helmet its head. The timber rattler lacks these large plates and has only small random shaped head scales. In addition, the tail of the timber rattlesnake is solid black just forward of its rattle.

"Massasauga" means "great river mouth" in Chippewa, so named because it is usually found in river bottom forests and nearby fields. Massasaugas are characteristic of mesic prairies and lowland places, such as along rivers, lakes, and marshes.

Wisconsin falls into the center of the massasauga's range which runs from central New York and southern Ontario to Iowa and Missouri. Historically, massasaugas were found across the southern half of Wisconsin. The draining and dredging of many wetland areas has resulted in much of their habitat being lost. Old records indicate that thousands of massasaugas were killed back in the late 1800's as the city of Milwaukee expanded. The bounty, which lasted until 1975, also played a role in the destruction of this species in Wisconsin.

Breeding takes place in the spring and the fall. Eight to 20 young are usually born in late August. Massasaugas are ovoviviparous, which means that the young are born live rather than from an external egg. They have a nonfunctional egg tooth which suggests that they may have evolved from egg layers. The newborn snakes are about the thickness of a lead pencil and could wrap around a silver dollar. They are typically born beneath a log, wood pile, or in abandoned mammal burrows. They stay inside the "nest" for about 4 or 5 days while they shed their skin the first of many times. The purpose of the "molt" is to replace the skin they are born with; the old skin has been stretched and aged due to the rapid growth of the developing young. The new skin will allow protection and growth until it is again stretched and worn. Massasaugas mature in 2-3 years and can live up to 14 years.

Massasaugas do not hibernate communally as do many other snake species. Instead they individually seek out crayfish or mammal burrows, sawdust piles, or old root canals. Crayfish burrows, which are built in river bottom dugouts with above ground mud chimneys, are the favorite of most massasaugas. Massasaugas hibernate in these burrows at or near water level. Since the massasauga cannot make its own burrows, other animals such as crayfish must be included in management plans to insure their preservation.

Massasaugas are active on warm, humid, overcast days and tend to sun themselves while coiled motionless in vegetation that conceals them. They are usually shy, secretive animals which rely on their coloration to avoid being detected. A common myth exists that all rattlesnakes will rattle before they strike. This is not always true, and the human tactic of listening for the rattle and killing the snake may be increasing the occurrence of rattlesnakes avoiding the use of the rattle.

The infamous rattles are actually modified epidermal scales with a bony core. Each time the snake sheds its skin a new "button" is added to the rattle, therefore these rattles are not an indication of age, but the amount of times the animal has shed its skin. Massasaugas can shed their skin between 3 and 5 times a year, depending on their health and growth rate. The rattles are believed to serve as warning communications to predators. The rattle produces a buzzing sound similar to that of a grasshopper or cricket.

The massasauga is a member of the "pit vipers" family. They were given this name because of the heat sensitive pits they have under each eye which alert the snake to prey or intruders. Massasaugas are preyed upon by raccoons, hogs, skunks, foxes, hawks, and eagles. They in turn will eat cold-blooded prey, such as frogs and other snakes, but they usually prefer warm-blooded prey like mice and voles.

Rattlesnakes attack their prey by striking. They must strike because their venom must be injected into the blood stream to be toxic. A three foot snake can strike about 12 inches or about one-third of its body size. The fangs of a massasauga are hollow and the venom is secreted into them by glands. When they are not in use, the fangs rotate and fold backward against the roof of its mouth. Massasaugas have the control to move each fang separately at will.

Since 1900, no one in the state of Wisconsin has died from a massasauga rattlesnake bite. Drop for drop, the massasauga's venom is more toxic than the timber rattler, but because of the smaller volume of venom, a bite would probably not cause severe harm to an adult human. Very few large domestic animals have ever been killed by rattlesnake bites. If the venom won't kill a human it won't have much effect on a horse or cow. The hog is usually unaffected by a rattlesnake bite because the layer of fat contained on its body prevents the fangs from injecting the venom into the blood stream. For this reason hogs are an efficient predator of rattlesnakes. Ever since the introduction of hogs to Wisconsin the numbers of rattlesnakes has decreased.

Many home remedies for rattlesnake bites have been used in the past, most of them based on folklore. Some of the external antidotes included: salt and onions; a mixture of gunpowder, salt and egg yolk; black mud and tobacco; ammonia; and many different concoctions including whiskey!

It is interesting to note that rattlesnakes can control the injection of venom when biting. Medical experts familiar with snake bites indicate that up to 60% of all snake bites to humans by poisonous snakes are "dry" bites containing no venom. Experts feel that the snakes may be voluntarily withholding the venom for use on prey and conserving it in some defense situations. However, these animals should always be treated with cautious respect.

The best thing to remember is that if you don't bother the massasauga it generally won't bother you. By wearing hiking boots and staying on the trail you can greatly reduce your chance of being bitten. If you are bitten, by knowing first aid and staying calm you can lessen the effects of the bite.

Status in WISCONSIN

There is no solid evidence of the numbers of massasaugas actually left in Wisconsin. The bounty on the species and loss of habitat are probably the major reasons for the species' decline. The massasauga is also a favorite captive venomous species, so native populations have suffered from illegal capturing of these animals for the pet trade. Today the massasauga is found only in several isolated localities in southeastern, central, and westcentral Wisconsin. They are endangered, and without management and added protection this species could be lost in Wisconsin and throughout its range. Endangered or threatened throughout most of its range, the massasauga is being considered for federal listing by the U.S. Fish & Wildlife Service.

No recovery or management plan is in place for this species in Wisconsin due in large part to a lack of information about the species. Life history studies have been proposed, and hopefully with the information gathered from these studies a management plan can be created. Without the protection of its wetland habitats, the massasauga has no chance for survival.

You can report any sightings of the massasauga or other endangered or threatened species to the Bureau of Endangered Resources. Observers should send digital photos to Robert Hay, or mail photos to BER's address (see below), or they can report them on the rattlesnake hotline (1-888-747-6253).
The Endangered and Threatened Species List is available from the Bureau if you want more information on what species are included. Unfortunately, as a species becomes more and more scarce, poaching and illegal capturing become more and more of a problem. Please report any violations of wildlife laws toll free to the Wisconsin Emergency Hotline at 1-800-847-9367.

Wisconsin Department of Natural Resources
Bureau of Endangered Resources
Attn: Robert Hay
P.O. Box 7921
Madison, WI 53707-7921

See Also:
Living with Snakes
Avoiding and Treating Timber Rattlesnake Bites

Excerpt from THE ENDANGERED AND THREATENED VERTEBRATE SPECIES OF WISCONSIN

Learn more about this publication...

Status: State Endangered (1975). Being considered for Federal Listing.

Occurrence: Historically, some of the largest known populations in the United States were found in southern Wisconsin. Currently they are found in westcentral and central Wisconsin.

Aid to ID: Medium-sized, stout-bodied snake. Adults 2 to 3 feet (60-90cm) in length. Head distinctly wider than neck, with 9 enlarged plate scales (not found on timber rattlesnake). Dorsal background: gray to earth brown with 20-40 multi-sized, mid-dorsal, chocolate brown blotches. Tail: light gray to yellow with 7 or less dark brown rings, ending with the pronounced rattle. Young have a bright yellowish "button" or tail end.

Habitat: Wet meadows, scrub, or lowland areas along rivers, lakes and marshes. Prefer river bottom lowland forests and adjacent open fields in active season. Gravid females prefer dry to dry-mesic prairies during the summer-long incubation period.

Food Habits: Primarily small rodents, but occasionally lizards, frogs, snakes and birds.

Natural History:

Active: April to October. Primarily diurnal, specifically early morning, but also active on warm summer evenings or throughout the day in warm, humid, overcast weather.
Hibernation: Alone, often in crayfish burrows, mammal burrows, on old root canals.
Reproduction: Mature at 3 to 4 years. Breed June to September. Females may only breed every other year. Give birth to 8 to 20 (avg. 15) live young, usually in late August.
Field Notes: Massasaugas are neither aggressive nor quick to rattle (their sound is similar to the buzz of an insect). Instead, they use cryptic coloration to avoid detection.

Management Considerations: Decline attributed to habitat destruction - primarily draining and filling of wetlands; collecting and killing, including a WI bounty that ended in 1975; vehicular traffic. Appear little affected by forest management practices. Natural succession of meadows (wet and dry) will reduce preferred habitat. Thus, management to maintain some open canopy for basking is recommended. Recent research indicates that drawdown management conducted in fall may jeopardize hibernating individuals in affected wetlands. Similarly, impounding sedge meadows and other wetlands will render habitat unsuitable for this species.

See Also:
Living with Snakes
Avoiding and Treating Timber Rattlesnake Bites

Information compiled from publications ER-511 94REV and ER-091.

Back to Top